1. Field of the Invention
This invention relates to a device for tensioning a shoe upper on a last and for laying its lasting margin over in the ball and shank region, wherein the shoe upper is pressed against the last by presser members by which pressure is applied to each side of the last, wherein there is fixed to each presser member a band which faces the shoe upper with its engaging surface and which, when the presser member lies adjacent the last, is drawn in the direction of the insole edge and about said edge in such a manner that the two bands meet substantially in the middle of the last bottom.
2. Description of Prior Art
Such a device is known from DE-OS No. 2650680. It serves to bring the shoe upper in the ball and shank region into a position suitable for a subsequent toe and side lasting operation and to hold the upper in this position during the lasting operation. In such a device the bands are drawn about the insole edge in such a way that they cross substantially in the middle of the last bottom and terminate in drafting elements which lie on the other side of the last in relation to the respective presser member, each band, beyond the cross-over position, being drawn, in a direction towards the drafting element, at a slight distance over that lasting margin about which the other band has been drawn. This distance must be maintained and thus a touching contact with the lasting margin at this position be avoided, because otherwise upon tensioning the band and its elastic yielding this lasting margin would be drawn downwardly away from the insole by the band in question. This distance, which has necessarily to be maintained, means that the band is increasingly distanced from that lasting margin about which it is drawn, in particular in a direction from the insole edge to the drafting element, so that an intensive application of pressure can arise only at the insole edge. Further inwardly, the pressure applied by the band to the lasting margin increasingly decreases. Furthermore, the crossing over of the bands leads to a certain displacement of the bands in relation to the longitudinal direction of the shoe, which shows inself noticeably undesired when, in use, there is a transition from a right to a left shoe or vice versa, since in this transition, even if a certain displacement is desired in relation to the one shoe, with the other shoe it appears in an undesired manner in the reverse direction. Finally in the known device it is to be noted that by the drafting force on the two bands which cross over, the insole of the shoe to be treated is not compressed. This tendency is furthered in that, because of the position of the bands, the shoe upper is tensioned in a direction towards the insole edge when the drafting effect is instituted and at the same time the lasting margin is drawn inwardly at least in the region of the insole edge.